1 /*
2 * Copyright (c) 2011, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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23 */
24
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP
27
28 #include "gc_implementation/g1/heapRegion.hpp"
29
30 // Large buffer for some cases where the output might be larger than normal.
31 #define HRS_ERR_MSG_BUFSZ 512
32 typedef FormatBuffer<HRS_ERR_MSG_BUFSZ> hrs_err_msg;
33
34 // Set verification will be forced either if someone defines
35 // HEAP_REGION_SET_FORCE_VERIFY to be 1, or in builds in which
36 // asserts are compiled in.
37 #ifndef HEAP_REGION_SET_FORCE_VERIFY
38 #define HEAP_REGION_SET_FORCE_VERIFY defined(ASSERT)
39 #endif // HEAP_REGION_SET_FORCE_VERIFY
40
41 class hrs_ext_msg;
42
43 class HRSMtSafeChecker : public CHeapObj<mtGC> {
44 public:
45 virtual void check() = 0;
46 };
47
48 class MasterFreeRegionListMtSafeChecker : public HRSMtSafeChecker { public: void check(); };
49 class SecondaryFreeRegionListMtSafeChecker : public HRSMtSafeChecker { public: void check(); };
50 class HumongousRegionSetMtSafeChecker : public HRSMtSafeChecker { public: void check(); };
51 class OldRegionSetMtSafeChecker : public HRSMtSafeChecker { public: void check(); };
52
53 class HeapRegionSetCount VALUE_OBJ_CLASS_SPEC {
54 friend class VMStructs;
55 uint _length;
56 size_t _capacity;
57
58 public:
59 HeapRegionSetCount() : _length(0), _capacity(0) { }
60
61 const uint length() const { return _length; }
62 const size_t capacity() const { return _capacity; }
63
64 void increment(uint length_to_add, size_t capacity_to_add) {
65 _length += length_to_add;
66 _capacity += capacity_to_add;
67 }
68
69 void decrement(const uint length_to_remove, const size_t capacity_to_remove) {
70 _length -= length_to_remove;
71 _capacity -= capacity_to_remove;
72 }
73 };
74
75 // Base class for all the classes that represent heap region sets. It
76 // contains the basic attributes that each set needs to maintain
77 // (e.g., length, region num, used bytes sum) plus any shared
78 // functionality (e.g., verification).
79
80 class HeapRegionSetBase VALUE_OBJ_CLASS_SPEC {
81 friend class VMStructs;
82 private:
83 bool _is_humongous;
84 bool _is_free;
85 HRSMtSafeChecker* _mt_safety_checker;
86
87 protected:
88 // The number of regions added to the set. If the set contains
89 // only humongous regions, this reflects only 'starts humongous'
90 // regions and does not include 'continues humongous' ones.
91 HeapRegionSetCount _count;
92
93 const char* _name;
94
95 bool _verify_in_progress;
96
97 // verify_region() is used to ensure that the contents of a region
98 // added to / removed from a set are consistent.
99 void verify_region(HeapRegion* hr) PRODUCT_RETURN;
100
101 // Indicates whether all regions in the set should be humongous or
102 // not. Only used during verification.
103 bool regions_humongous() { return _is_humongous; }
104
105 // Indicates whether all regions in the set should be free or
106 // not. Only used during verification.
107 bool regions_free() { return _is_free; }
108
109 void check_mt_safety() {
110 if (_mt_safety_checker != NULL) {
111 _mt_safety_checker->check();
112 }
113 }
114
115 virtual void fill_in_ext_msg_extra(hrs_ext_msg* msg) { }
116
117 HeapRegionSetBase(const char* name, bool humongous, bool free, HRSMtSafeChecker* mt_safety_checker);
118
119 public:
120 const char* name() { return _name; }
121
122 uint length() const { return _count.length(); }
123
124 bool is_empty() { return _count.length() == 0; }
125
126 size_t total_capacity_bytes() {
127 return _count.capacity();
128 }
129
130 // It updates the fields of the set to reflect hr being added to
131 // the set and tags the region appropriately.
132 inline void add(HeapRegion* hr);
133
134 // It updates the fields of the set to reflect hr being removed
135 // from the set and tags the region appropriately.
136 inline void remove(HeapRegion* hr);
137
138 // fill_in_ext_msg() writes the the values of the set's attributes
139 // in the custom err_msg (hrs_ext_msg). fill_in_ext_msg_extra()
140 // allows subclasses to append further information.
141 void fill_in_ext_msg(hrs_ext_msg* msg, const char* message);
142
143 virtual void verify();
144 void verify_start();
145 void verify_next_region(HeapRegion* hr);
146 void verify_end();
147
148 #if HEAP_REGION_SET_FORCE_VERIFY
149 void verify_optional() {
150 verify();
151 }
152 #else // HEAP_REGION_SET_FORCE_VERIFY
153 void verify_optional() { }
154 #endif // HEAP_REGION_SET_FORCE_VERIFY
155
156 virtual void print_on(outputStream* out, bool print_contents = false);
157 };
158
159 // Customized err_msg for heap region sets. Apart from a
160 // assert/guarantee-specific message it also prints out the values of
161 // the fields of the associated set. This can be very helpful in
162 // diagnosing failures.
163 class hrs_ext_msg : public hrs_err_msg {
164 public:
165 hrs_ext_msg(HeapRegionSetBase* set, const char* message) : hrs_err_msg("%s", "") {
166 set->fill_in_ext_msg(this, message);
167 }
168 };
169
170 #define hrs_assert_sets_match(_set1_, _set2_) \
171 do { \
172 assert(((_set1_)->regions_humongous() == \
173 (_set2_)->regions_humongous()) && \
174 ((_set1_)->regions_free() == (_set2_)->regions_free()), \
175 hrs_err_msg("the contents of set %s and set %s should match", \
176 (_set1_)->name(), (_set2_)->name())); \
177 } while (0)
178
179 // This class represents heap region sets whose members are not
180 // explicitly tracked. It's helpful to group regions using such sets
181 // so that we can reason about all the region groups in the heap using
182 // the same interface (namely, the HeapRegionSetBase API).
183
184 class HeapRegionSet : public HeapRegionSetBase {
185 public:
186 HeapRegionSet(const char* name, bool humongous, HRSMtSafeChecker* mt_safety_checker):
187 HeapRegionSetBase(name, humongous, false /* free */, mt_safety_checker) { }
188
189 void bulk_remove(const HeapRegionSetCount& removed) {
190 _count.decrement(removed.length(), removed.capacity());
191 }
192 };
193
194 // A set that links all the regions added to it in a doubly-linked
195 // sorted list. We should try to avoid doing operations that iterate over
196 // such lists in performance critical paths. Typically we should
197 // add / remove one region at a time or concatenate two lists.
198
199 class FreeRegionListIterator;
200
201 class FreeRegionList : public HeapRegionSetBase {
202 friend class FreeRegionListIterator;
203
204 private:
205 HeapRegion* _head;
206 HeapRegion* _tail;
207
208 // _last is used to keep track of where we added an element the last
209 // time. It helps to improve performance when adding several ordered items in a row.
210 HeapRegion* _last;
211
212 static uint _unrealistically_long_length;
213
214 inline HeapRegion* remove_from_head_impl();
215 inline HeapRegion* remove_from_tail_impl();
216
217 protected:
218 virtual void fill_in_ext_msg_extra(hrs_ext_msg* msg);
219
220 // See the comment for HeapRegionSetBase::clear()
221 virtual void clear();
222
223 public:
224 FreeRegionList(const char* name, HRSMtSafeChecker* mt_safety_checker = NULL):
225 HeapRegionSetBase(name, false /* humongous */, true /* empty */, mt_safety_checker) {
226 clear();
227 }
228
229 void verify_list();
230
231 #ifdef ASSERT
232 bool contains(HeapRegion* hr) const {
233 return hr->containing_set() == this;
234 }
235 #endif
236
237 static void set_unrealistically_long_length(uint len);
238
239 // Add hr to the list. The region should not be a member of another set.
240 // Assumes that the list is ordered and will preserve that order. The order
241 // is determined by hrm_index.
242 inline void add_ordered(HeapRegion* hr);
243
244 // Removes from head or tail based on the given argument.
245 HeapRegion* remove_region(bool from_head);
246
247 // Merge two ordered lists. The result is also ordered. The order is
248 // determined by hrm_index.
249 void add_ordered(FreeRegionList* from_list);
250
251 // It empties the list by removing all regions from it.
252 void remove_all();
253
254 // Remove all (contiguous) regions from first to first + num_regions -1 from
255 // this list.
256 // Num_regions must be > 1.
257 void remove_starting_at(HeapRegion* first, uint num_regions);
258
259 virtual void verify();
260
261 virtual void print_on(outputStream* out, bool print_contents = false);
262 };
263
264 // Iterator class that provides a convenient way to iterate over the
265 // regions of a FreeRegionList.
266
267 class FreeRegionListIterator : public StackObj {
268 private:
269 FreeRegionList* _list;
270 HeapRegion* _curr;
271
272 public:
273 bool more_available() {
274 return _curr != NULL;
275 }
276
277 HeapRegion* get_next() {
278 assert(more_available(),
279 "get_next() should be called when more regions are available");
280
281 // If we are going to introduce a count in the iterator we should
282 // do the "cycle" check.
283
284 HeapRegion* hr = _curr;
285 _list->verify_region(hr);
286 _curr = hr->next();
287 return hr;
288 }
289
290 FreeRegionListIterator(FreeRegionList* list) : _curr(NULL), _list(list) {
291 _curr = list->_head;
292 }
293 };
294
295 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSET_HPP